Re: [ATM] mobsby null test

["Don D'Egidio" <djd521@comcast.net>]

Guy,

What's the F ratio of the mirror your are testing. The Mosby Null Test is intended for mirrors F8 and slower.

Don

----- Original Message ----- 
From: "Guy Brandenburg" <gfbrandenburg@yahoo.com>
To: <atm@atmlist.net>
Sent: Saturday, August 07, 2004 21:53
Subject: [ATM] mobsby null test


> I and a couple of others have just finished attempting
> to use the Mobsby Null Test that is sold by
> Willmann-Bell, and I have to say that I am extremely
> frustrated. It took me quite a while to fabricate a
> really high-intensity light source (we cannibalized
> some Ikea halogen lights for their switch, their
> transformer, and their light bulbs). We also used a
> fairly large fan to keep everything from getting too
> hot. I made a box to house everything, partly from
> wood and partly from sheet metal. We frosted some
> glass, manually, and made a teeny-tiny hole in some
> glass. But everything is so tiny that we ended up not
> really being able to see much of anything. In fact,
> when I used the built-in knife-edge, sometimes it
> seemed to cut off a shadow fromt he right; sometimes
> from above; and sometimes from above, all without me
> doing much of anything. As far as seeing anything like
> what I thought you were supposed to see with the
> 3-line reverse Mobsby Null test -- hah!
> 
> Has anybody else actually tried using one of these
> slides, and with how much success?
> 
> Guy Brandenburg
> 
> =====
> Guy  Brandenburg
> Washington, DC
> My home page:
> http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
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> ATM mailing list http://www.atmlist.net/

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